#[non_exhaustive]pub enum TargetVisualOptions {
AllVisuals,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against TargetVisualOptions
, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let targetvisualoptions = unimplemented!();
match targetvisualoptions {
TargetVisualOptions::AllVisuals => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when targetvisualoptions
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant TargetVisualOptions::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
TargetVisualOptions::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str
on it yields "NewFeature"
.
This match expression is forward-compatible when executed with a newer
version of SDK where the variant TargetVisualOptions::NewFeature
is defined.
Specifically, when targetvisualoptions
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on TargetVisualOptions::NewFeature
also yielding "NewFeature"
.
Explicitly matching on the Unknown
variant should
be avoided for two reasons:
- The inner data
UnknownVariantValue
is opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
AllVisuals
Unknown(UnknownVariantValue)
Unknown
. See the docs on this enum for the correct way to handle unknown variants.Unknown
contains new variants that have been added since this code was generated.
Implementations§
source§impl TargetVisualOptions
impl TargetVisualOptions
sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
source§impl AsRef<str> for TargetVisualOptions
impl AsRef<str> for TargetVisualOptions
source§impl Clone for TargetVisualOptions
impl Clone for TargetVisualOptions
source§fn clone(&self) -> TargetVisualOptions
fn clone(&self) -> TargetVisualOptions
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for TargetVisualOptions
impl Debug for TargetVisualOptions
source§impl Display for TargetVisualOptions
impl Display for TargetVisualOptions
source§impl From<&str> for TargetVisualOptions
impl From<&str> for TargetVisualOptions
source§impl FromStr for TargetVisualOptions
impl FromStr for TargetVisualOptions
source§impl Hash for TargetVisualOptions
impl Hash for TargetVisualOptions
source§impl Ord for TargetVisualOptions
impl Ord for TargetVisualOptions
source§fn cmp(&self, other: &TargetVisualOptions) -> Ordering
fn cmp(&self, other: &TargetVisualOptions) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq for TargetVisualOptions
impl PartialEq for TargetVisualOptions
source§impl PartialOrd for TargetVisualOptions
impl PartialOrd for TargetVisualOptions
impl Eq for TargetVisualOptions
impl StructuralPartialEq for TargetVisualOptions
Auto Trait Implementations§
impl Freeze for TargetVisualOptions
impl RefUnwindSafe for TargetVisualOptions
impl Send for TargetVisualOptions
impl Sync for TargetVisualOptions
impl Unpin for TargetVisualOptions
impl UnwindSafe for TargetVisualOptions
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)source§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more